updated 04:05 pm EDT, Tue June 17, 2014

Slingshot requires response before reading incoming messages

Facebook has launched its Snapchat competitor for a second time, following its accidental release and retraction earlier this month. Slingshot, out for both iOS and Android in the United States, allows users to pass messages, images, and video to each other, though the recipient will not be able to read the message until they "react" with their own message.

"Shots" to be sent to others can consist of a video, up to 15 seconds in length, a photograph, or a text-based reaction. Captioning and drawing tools are available for editing the shot before sending it, with messages able to be sent to an individual or a number of people at the same time. In a nod to the temporary nature of Snapchat, shots "unlocked" by reciprocal messaging will get deleted once they are swiped off the smartphone, though they will be viewable for up to 30 days if the user chooses to keep the shot from unlocking until later. Photographs and videos taken with the app for sending can be saved to the device, but received items cannot be saved in this way.

It is difficult to gauge how the app will be received by potential users. Forcing people to send a message in order to read one they have just received could be considered too much work compared to the more passive nature of Snapchat. Privacy could also be an issue, as Snapchat came under fire from the FCC for deletion issues. There is also the question of trust in Facebook, with the social network running into trouble with the FTC in the past in relation to exposing private information, something users of the service may want to be wary of.